Like most things, the title of “best iPhone 6 battery case” is subject to change whenever something new and great shows up to challenge existing options, and as the iPhone 6 is still young, we’re expecting a lot of jockeying for position over the next few months. The latest real contender comes from iBattz, maker of some of the best iPhone battery cases I’ve tested. Refuel Invictus for iPhone 6 ($100, aka Mojo Refuel Invictus) is the first iPhone 6 case to include a great feature from some earlier iPhone 4/4S and 5/5s cases: removable, replaceable batteries.

Using solely the items in its own box, Refuel Invictus delivered the largest recharge I’ve seen yet for the iPhone 6: 127%, or a full recharge plus an additional 27%. That might be enough to justify the asking price for some people. But you can also add a second battery and external USB charger for $25-$30 more. If you’ve been hunting for a slim battery case that can keep your iPhone running endlessly, this might be the most cost-effective way to do it.

It’s a great time to buy an iPhone 6 battery case. Last year, there were zero Apple-certified options, but today, there are a handful of good to great choices at various price points. They may look similar to each other in the picture above, but the sea of black shells masks some important differences in iPhone protection, battery recharging capabilities, and pricing. We now have two top picks for the iPhone 6, as well as two completely different top picks for the iPhone 6 Plus. Note that the iPhone 6 versions typically work with the newer iPhone 6s, and the iPhone 6 Plus versions work with the iPhone 6s Plus; both of the “s” models have slightly smaller batteries than their predecessors.

Which battery case should you buy? The most recent update to this piece on October 6, 2015 added another new option! Read on for all the details…

There is a never ending supply of new iPhone cases at CES again this year, so we’ve decided to roundup the best of the best below. Some of the cases include backup batteries, others offer charging via built-in solar panels, and one includes a detachable Bluetooth speaker. One of the new cases even claims to “defend against the bend,” a jab at the iPhone 6 Plus bending controversy of last year. Head below for the run down on the growing list of iPhone cases launching at CES: expand full story